1. Field of the Invention
The present invention relates to shock absorbing materials which are excellent in dynamic compression characteristic.
2. Description of the Prior Art
The evaluation of the compression characteristic of shock absorbing materials has heretofore been evaluated conventionally by a static compression test. On the static compression characteristic, for example, a static compression characteristic curve as shown in FIG. 1 is believed to be ideal in view of an efficiency of energy absorption.
However, even if a shock absorbing material has an ideal static compression characteristic as shown in FIG. 1, when the shock absorbing material is tested as to its dynamic compression, the dynamic compression characteristic curve is formed as shown in FIG. 2 in which the leading edge of the load is dull and accordingly, a disadvantage is encountered that the efficiency of energy absorption is poor.
In FIG. 1, the axis of abscissa denotes a displacement, and the axis of ordinate denotes a static load applied to the shock absorbing material. In FIG. 2, the axis of abscissa denotes a displacement, and the axis of ordinate denotes a dynamic load applied to the shock absorbing material.